charging system going crazy

[jdub]

hey all,
looking for a little help here on a charging system problem. I have an 81 XS1100SH Special. the voltage reading from my battery is going crazy. it will read from 1.78 volts to 12.6 volts while running. it does not level out for more than a second. it's just all over the place. voltage is steady at 12.18 volts when off and 11.48 volt with the key on and the engine off. i have checked and cleaned the connections at the regulator/rectifier and the stator connections behind the fuse panel, the battery was new 4 mos ago. i did replace the headlight/turn signal switch with a universal one and there are some lines that weren't hooked back up, but the functionality of the turn signals and headlight are fine. the headlight does turn on after the bike is started as normal. i cleaned the fuse panel also. i did not get a voltage reading before replacing the turn/ headlight switch. i did also notice my key switch does have a little play in the on position, i have to wiggle it a bit before it powers up the bike.

any help would be greatly appreciated...

[GLoweVA]

Let me be the first to welcome you to the madness.
That key switch needs to be fixed. You'd hate to lose all power while riding down the road and the bike shuts off.
It can easily be disassembled and cleaned and even a little grease to make it smooth. There's a thread somewhere on here about it.

Next. It sounds like the battery is fine.
The head light is coming on like it should becasue the latching relay gets power from the alt.
Is your tach functioning correctly? I bet it is.
Therefore the problem is in the rectifier or the connection from there back to the battery.

You can download a copy of the manual on CatatonicBug's site:
http://www.ringler.us/family/mybike.html
There you'll find a wiring diagram to help you trace lines.

[jdub]

Thank you for the welcome. the link is much appreciated. this site has already been a big help in getting my bike almost road worthy. had to do the 2nd gear fix/ washer move. and yes the tach works fine. i have a replacement regulator coming, so i hope it works. thanks again

[natemoen]

Where is it that you are getting your voltage readings from?

[jdub]

i am taking the readings from the battery terminals with my multimeter.

[DAVINCI]

I'll bet your multimeter is a digital one?

[jdub]

it is. a cheap one at that too. . .

[Winterhawk]

What happened to me last night was a charging issue. My headlight was on as soon as the key was turned on with the headlight switch off. Grounding the green wire did nothing to the charging. It turned out being a shorted voltage regulator. The headlight control relay was so hot that I could barley touch it.

My hi cap battery allowed me to go the 20 miles with lights on and no charge. Must of been why my Tach quit earlier in the day. My other VR's are toast so I got one from e-Bay till I can figure out how to buy a Geezer one.

[jdub]

the voltage never gets above 12.6 volts at any time. that's why i am worried about it. most say it should be running 14.6 volts at 3000 rpm, this doesn't change no matter the rpm, i haven't gone on a ride more than a few blocks since i don't see 14 volts. i also did the feeler gauge against the generator housing, it does pull it down and push it away every revolution, so it is bouncing alot. not sure if that is normal or not.

[motoman]

Before condemmig any components, as GLoweVA stated, ignition switch contacts AND most likely kill switch(completes ignition circuit whether used or not) are likely suspect, on top of some poor grounds, and there are several.

[GLoweVA]

Before condemmig any components, as GLoweVA stated, ignition switch contacts AND most likely kill switch(completes ignition circuit whether used or not) are likely suspect, on top of some poor grounds, and there are several.

Moto, you're right, everything should be checked/cleaned before starting to replace anything.
The key switch has to be the first thing that needs TLC.
If his problem is fixed, then great, if not, then the kill switch. (again easy to take apart and clean up)
Obviously his alternator is working, (tach and feeler gauge are evidence) but something is limiting the voltage back to the battery.
The manual has a check that can be performed on the rectifier to see if all the diodes in there are working. (I could guess that if one set of diodes were bad then the output from the rectifier would be lower thus not giving the full 14V output)

Question: After the bike is running, could he pull the positive lead off the battery? Should the bike still run on it's own? And then measure the battery lead voltage. (should be whatever the output of the reg/rec is)

[motoman]

Moto, you're right, everything should be checked/cleaned before starting to replace anything.
The key switch has to be the first thing that needs TLC.
If his problem is fixed, then great, if not, then the kill switch. (again easy to take apart and clean up)
Obviously his alternator is working, (tach and feeler gauge are evidence) but something is limiting the voltage back to the battery.
The manual has a check that can be performed on the rectifier to see if all the diodes in there are working. (I could guess that if one set of diodes were bad then the output from the rectifier would be lower thus not giving the full 14V output)

Question: After the bike is running, could he pull the positive lead off the battery? Should the bike still run on it's own? And then measure the battery lead voltage. (should be whatever the output of the reg/rec is)

Doubtful, don't think system is isolated and DOES operate from batt.. Know where your headed......but no outlet.

[jdub]

Question: After the bike is running, could he pull the positive lead off the battery? Should the bike still run on it's own? And then measure the battery lead voltage. (should be whatever the output of the reg/rec is)

From what i have read of other xs owners problems, the battery is needed for the bike to run. so i have not tried to disconnect the battery.

i have noticed the taillight fuse holder and headlight fuse holder do get very hot, so it may be a grounding problem?

[red bandit]

Any connection, plug or fuse holder that is getting warm/hot means it's a bad connection. Clean it. Do yourself a favor. Start from one end of the bike and work towards the other, clean every connection there is, including all grounds.

[motoman]

I'll bet your multimeter is a digital one?

Havin' both, I sure like the anolog when jiggleing things around seeing the actual movement(even if slight) of that needle. Either one $10 or less at Sears, and saves a whole lot of head-scratchin'......